The Design and Implementation of the 4.4BSD Operating System Marshall Kirk McKusick Keith Bostic Michael J. Karels John S. Quarterman Copyright © 1996 Addison-Wesley Longman, Inc The second chapter of the book, The Design and Implementation of the 4.4BSD Operating System is excerpted here with the permission of the publisher. No part of it may be further reproduced or distributed without the publisher's express written permission. The rest of the book explores the concepts introduced in this chapter in incredible detail and is an excellent reference for anyone with an interest in BSD UNIX. More information about this book is available from the publisher, with whom you can also sign up to receive news of related titles. Information about BSD courses is available from Kirk McKusick. [ Split HTML / Single HTML ] Table of Contents 2 Design Overview of 4.4BSD 2.1 4.4BSD Facilities and the Kernel 2.1.1 The Kernel 2.2 Kernel Organization 2.3 Kernel Services 2.4 Process Management 2.4.1 Signals 2.4.2 Process Groups and Sessions 2.5 Memory Management 2.5.1 BSD Memory-Management Design Decisions 2.5.2 Memory Management Inside the Kernel 2.6 I/O System 2.6.1 Descriptors and I/O 2.6.2 Descriptor Management 2.6.3 Devices 2.6.4 Socket IPC 2.6.5 Scatter/Gather I/O 2.6.6 Multiple Filesystem Support 2.7 Filesystems 2.8 Filestores 2.9 Network Filesystem 2.10 Terminals 2.11 Interprocess Communication 2.12 Network Communication 2.13 Network Implementation 2.14 System Operation References List of Tables 2-1. Machine-independent software in the 4.4BSD kernel 2-2. Machine-dependent software for the HP300 in the 4.4BSD kernel List of Figures 2-1. Process lifecycle 2-2. A small filesystem Chapter 2 Design Overview of 4.4BSD 2.1 4.4BSD Facilities and the Kernel The 4.4BSD kernel provides four basic facilities: processes, a filesystem, communications, and system startup. This section outlines where each of these four basic services is described in this book. Processes constitute a t